The present invention relates to a tear-along structure of a sheet material, and particularly to a tear-along structure of a sheet material suitable for a polygon roll design of an adhesive tape.
The conventional long yard membranes are all rolled up in a cylindrical shape, such as a roll of toilet paper. In order to achieve the easy tear feature during operation, the pressed veins or hole-piercing (i.e. punched as the dotted lines) at predetermined length""s positions are utilized. Particularly, in the application of the adhesive tape, for example, the Taiwanese Patent Application No.7224090 filed on Jun. 21, 1983 and entitled xe2x80x9cPoint-cut typed adhesive plastic tapexe2x80x9d, a point-cut typed OPP (oriented polypropylene) adhesive tape has been disclosed, which is characterized by piercing hole on this adhesive tape. Furthermore, e.g. in the Taiwanese Patent Application No. 77211389 filed on Dec. 5, 1988 and entitled xe2x80x9cTraverse type of new patterned adhesive tapexe2x80x9d, a design of xe2x80x9cTraverse type of new patterned adhesive tapexe2x80x9d is disclosed, which is set with a gradually layered guide angle at the side edge of the main body of an adhesive tape and applied the partial back glue to said adhesive tape. And part of the unglued area near the side of the gradually layered guide angle is reserved for the pulling up position of adhesive tape. In addition, the cutting groove is set on the surface of the adhesive tape, and a strip shaped adhesive tape is formed between two cutting grooves.
In recent years, an adhesive tape with minute orifice structure produced by a minute processing technology has been developed to provide a product with the feature of easy tear in every direction. However, this kind of adhesive tape is difficult to bring about an ordered slit while tearing due to the limpness of adhesive tape itself.
The object of the present invention is to provide a tear-along structure of a sheet material suitable for a polygon roll design of the adhesive tape which is characterized in that:
a membrane substrate is wrapped around a polygonal core lining, and a slit is cut into at least one edge corresponding to a crest line of each corner of the core lining. The slit is cut deeply into the said core lining.
According to the present invention, the substrate is torn from the slit; and with the crest line formed by a curvature of the substrate at the corner, the substrate is leaned against this crest line and torn along this crest line orderly.